Sofia Carson wrote her Songbird character's backstory

Sofia Carson has opened up about her methods for developing her character Sara's backstory in pandemic themed thriller, Songbird.

The Adam Mason directed film stars KJ Apa as Nico and Carson as Sara, a couple who can only be together virtually as they struggle in a world where COVID-19 has mutated into COVID-23.

Speaking to Buzzfeed, Carson said that Mason offered her and Apa lots of leeway to create their characters for the sci-fi film.

"(Mason) didn't tell us who Sara and Nico were, he wanted us to write their story," she explained.

"Before we started shooting, I sat down that weekend and I wrote Sara's story from start to finish. Where she was born, who her mother was, her relationship with her mom, what her fears are, how she met Nico, everything that made Sara who she is in order to bring her to life," Carson shared.

The actress then revealed that she and Apa collaborated on the fictional couple's relationship journey.

"We got together that weekend, that Saturday, and we spent the whole day bringing our love story to life: the first moment Sara and Nico met, the thing about Sara that made Nico fall for her, someone he's never seen, only someone he's heard through the door," Carson recollected.

"I made a playlist for Sara and Nico and I called it 'Our Playlist.' In my mind, it was something that they had made together," she divulged.

Songbird was released to video-on-demand services on December 11.